In the field of magnetic heads to be mounted on a magnetic recording/reproducing apparatus such as a hard disk drive (HDD), recently, the flying height of a magnetic head to be mounted has been dramatically decreased along with improvement in recording density, falling below 10 (nm). However, there is a problem that such a decrease in the flying height causes the phenomenon of generating frictional heat due to collision of the magnetic head against a ridge on the surface of a magnetic disk, so-called thermal asperity (hereinafter referred to as TA).
Occurrence of TA not only damages the magnetic head by collision but also adversely affects write signals and read signals because the resistance of a magneto-resistive effect element momentarily changes along with an increase in temperature due to frictional heat.
Concerning this problem, for example, Japanese Unexamined Patent Application Publication No. 2007-310978 discloses a technology of providing the magnetic head with a heater and controlling the flying height based on detected TA utilizing thermal expansion due to heating by the heater. However, since this technology is based on the premise that a TA detection circuit is disposed outside the magnetic head, the apparatus increases in size, which is not desirable from the viewpoint of miniaturization.
Accordingly, the magnetic head itself has been required to have the function of detecting TA and there has been developed a technology of utilizing the magneto-resistive effect element, which is the reproducing element, as the TA detection element. However, when using a recently prevailing TMR (tunnel magneto-resistance) element, there is a problem that since it has a low temperature coefficient, the change in resistance due to heat is too small to obtain desired detection sensitivity. With this technology, moreover, the reproducing element collides against a ridge of the magnetic disk, which is not desirable from the viewpoint of reliability.
On the other hand, for example, Japanese Unexamined Patent Application Publication No. 11-306514 discloses a technology of providing a TA detection element separately of the reproducing element. This technology is such that in the vicinity of a magneto-resistive effect element, a resistive element having a lower temperature coefficient than the above element is formed and electrically connected to the magneto-resistive effect element to compensate the change in signals due to TA or the like. However, this has a problem that there is a limit to selection of temperature coefficient.